Sony DTV-01, Manual

Page: 28 / 132

31
Video Process A
The external video input from the rear panel and internal video from both
main and sub tuners is applied to this stage for selection and conversion
to (Y, R-y, B-y) component video. The major parts in this early video pro-
cessing are listed below:
Major Video Processing Components Shown
Name Input Output Purpose
Video Switch
IC2006
2 tuners,
3 video inputs
Y & C from 2
comb filters
Main Y & C
Sub Y & C
(similar
processing not
shown)
Selects
composite
video
Routes to comb
filter
Buffers Q2016,
Q2420, Q2422. 1Vp-p of Y from
IC2006/pin 35 1Vp-p of Y to
IC2406/pin 28 Y buffers
YUV Switch ½
IC2406 1Vp-p of Y at
IC2406/pin 28 2Vp-p at pin 22 6db amp
Buffers Q2015,
Q2421 1Vp-p of C
from
IC2006/pin 31 1Vp-p of C to
IC2404/pin 32 C buffers
Chroma
Decoder
IC2404 Main Y & C at
pins 34 and 32
Y=2Vp-p,
C=1Vp-p
Y = 1Vp-p;
Cr, Cb = 0.5Vp-
p @ pins 18-20
Changes Y/C
to component
video
All signal levels were taken using a color bar input.
Video Switch
Five composite video inputs are applied to video switch IC2006. Serial
data from Main Micro IC3251 (not shown) chooses which input signals
take the main and sub picture signal paths. The chosen signals go to their
respective comb filters. The 3D filter is always kept in the main picture
path and the glass filter (FL2001) is used in the sub picture path.
The Y & C outputs from both comb filters are returned to IC2006 and
output again. The main picture path is from pins 31 and 35. The sub video
path is from switch IC2006/pins 25 and 30 and runs a parallel route to the
main one (Video Block 1) for identical processing.
Component Video
Then the Y signal is input the Chroma Decoder. The chroma (C) signal is
also buffered and input to Chroma Decoder IC2404/pin 32. IC2404 uses
both the Y & C inputs for level conversion to Y, Cr, Cb (component video).